Fishy Leg Story

Fishy leg story reported in ScienceDaily 10 December 2012 and New Scientist 15 December 2012. In an attempt to see how fish fins could have developed into legs in order for evolving land animals to take their first steps, Fernando Casares of the Spanish National Research Council and colleagues injected zebrafish embryos with extra copies of a gene named hoxd13. This gene codes for a protein that stimulates cartilage development in fin and limb buds of developing embryos. In a fish embryo the fin buds have a small region of cartilage development close to the body and the rest of the bud forms a finfold, which develops into a fin. In land animals the developing limb is called an “autopod” and contains a large region of cartilage formation. The zebrafish with the extra hoxd13 developed a large region of cartilage growth with a reduced finfold – similar to an autopod in an embryonic land animal. The researchers also gave zebrafish embryos a DNA control element that enhances the expression of the hoxd13gene in mice, but is not present in fish, and got the same results. The researchers concluded that fins evolved into limbs “by acquisition of novel enhancer elements” of the hoxd13gene.

Editorial Comment: Sounds great until you read that the experimental fish did not actually grow legs, and worse than that, New Scientist reports: “They carried on growing for four days but then died”. Therefore, these experiments do not explain how control element could be acquired by chance random processes, and likewise they tell us nothing about how fins could evolve into limbs.

Intelligent scientists, who were outside the fish, acted to enhance the expression of the hoxd13 gene by adding extra copies of the gene or the control element. However, since all they produced was dead fish with messed up fins, the scientists were not much good at creating, and they certainly did not help fish evolve as a new form of living creatures which could out-perform their non-evolving fellow creatures, and so reproduce and pass on whatever “novel enhancer elements” they may have acquired to the next generation.

Again we repeat - it is far more logical to believe a much more intelligent Creator made fish and land animals, and gave them the appropriate genes and control elements to make fins or limbs, along with all the other features needed to be fish or land animals. (Ref. ichthyology, embryology, morphogenesis)